\section*{Acknowledgement}

First and foremost, I am sincerely grateful to faculty members in Murai and Tokuda Laboratory, Professor Hideyuki Tokuda, Professor Jun Murai, Associate Professor Hiroyuki Kusumoto, Professor Osamu Nakamura, Associate Professor Kazunori Takashio, Assistant Professor Noriyuki Shigechika, Assistant Professor Rodney D. Van Meter III, Associate Professor Keisuke Uehara, Associate Professor Jin Mitsugi, Lecturer Jin Nakazawa.

I would be extremely thankful to Professor Keiji Takeda for his endless help and valuable comments to my thesis. Without his help, I cannot even think of writing this thesis.

I own my special thank to Doctor Masayoshi Mizutani for his sincerely help and many advices since the time I first came to the lab.

I would like to thank to Master Kunihiko Shigematsu, Yuki Uehara, my friend Toshinori Usui, for listening	and giving me many useful discussion points. Their gentleness and encouragement helped me overcome many hard times in this one year. 
 
I would also like to thank all ISC group members, Sega-kun, Alc-kun, Lushe-kun, Nobita-kun, Fuyuki-kun, Yoshi-kun, Asp-chan, Hino-kun, Rocky-kun, Vigo-kun, who have given me numerous support and always cheer me up in my hard times. 

I would like to thank to members in Murai and Tokuda Laboratory who have been so friendly and kindly supporting me with my research.

